Security readout for executives and security teams
Plain-English summary
CVE-2020-3117 lets a remote unauthenticated attacker inject HTTP headers into responses from affected Cisco security appliances if they can persuade a user to open a crafted URL. The direct impact is limited to response integrity, not confirmed data theft or outage.
Executive priority
Treat this as a medium-priority appliance hygiene issue. It is not confirmed exploited and has limited integrity impact, but affected security infrastructure should be checked and updated under normal vulnerability management timelines.
Technical view
Cisco describes insufficient input validation in the API Framework of AsyncOS for Cisco WSA and SMA. The flaw is CWE-113 HTTP header injection. CVSS 3.0 is 4.7 with network access, low attack complexity, no privileges, required user interaction, changed scope, and low integrity impact.
Likely exposure
Exposure is most relevant to organizations running Cisco Web Security Appliance or Content Security Management Appliance with the affected AsyncOS API Framework. Risk increases where appliance web interfaces are reachable by users who could be lured to crafted URLs.
Exploitation context
The provided sources do not show active exploitation, and the CVE is not marked KEV. Exploitation requires user interaction: an attacker must persuade a user to access a crafted URL and receive a manipulated HTTP response.
Researcher notes
Evidence is limited to the CVE metadata and Cisco advisory reference. Do not assume affected versions, exploit availability, or fixed releases beyond Cisco’s published guidance. The key technical behavior is response header injection after crafted URL interaction.
Mitigation direction
- Inventory Cisco WSA and SMA deployments and their AsyncOS versions.
- Review Cisco’s advisory for fixed releases or official workarounds.
- Apply Cisco-provided updates or mitigations where applicable.
- Limit appliance web/API access to trusted administrative networks while assessing.
- Monitor Cisco PSIRT and CVE updates for revised guidance.
Validation and detection
- Confirm whether any deployed WSA or SMA matches Cisco’s affected product scope.
- Check installed AsyncOS versions against Cisco advisory guidance.
- Verify appliance web/API interfaces are not broadly exposed.
- Review logs for suspicious crafted URL access patterns where available.
- Document remediation status and remaining compensating controls.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-113: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2020-3117 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Medium
- CVSS
- 4.7 (3.0)
- Known Exploited
- No
- Published
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:L/A:N
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:L/A:N2.81.4Primary CVE scoreVulnerability scoring details
Base CVSS 3.0 score
4.7MediumVector: CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:L/A:N
Source materials
- CVE List V5 sourceCVE List V5
- 20200122 Cisco Web Security Appliance and Cisco Content Security Management Appliance HTTP Header Injection VulnerabilityCVE reference · vendor-advisory, x_refsource_CISCO
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Request/Response Splitting')
Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Request/Response Splitting') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.